1. Field of the Invention
The present invention relates to a semiconductor device, and a method of manufacturing the semiconductor device.
2. Description of the Background Art
FIGS. 20A and 20B are diagrams of an existing IGBT module 900. FIG. 20A is a top view. FIG. 20B is a sectional view cut along a line 20B-20B of FIG. 20A. Herein, an upper cover and gel filling the interior are not shown in the drawings.
The IGBT module 900 includes a heat release plate 51, an insulating substrate 53 fixed with solder 52 on the heat release plate 51, and a semiconductor element 55 fixed with solder 54 on the insulating substrate 53. Also, the IGBT module 900 includes an insert terminal case 57 fixed with adhesive 56 on the heat release plate 51, and bonding wire 58 fixed to the insert terminal case 57, semiconductor element 55, and insulating substrate 53. The insert terminal case 57 includes a resin case 59 and an external lead-out terminal 60. The external lead-out terminal 60 includes an internal terminal 61 (inner lead), and an external terminal 62 (outer lead) connected at a right angle to the internal terminal 61. An inner wall 59a of the resin case 59 has an L-form, and the resin case 59 includes an upper side vertical resin portion 63 (hereafter called simply a vertical resin portion), and a horizontal resin portion 64 and lower side vertical resin portion 65 linked to the vertical resin portion 63. The external terminal 62 is inserted with the leading end thereof being exposed into the vertical resin portion 63, and the internal terminal 61 is embedded with the surface thereof being exposed in a groove 66 formed in the horizontal resin portion 64. Although it is desirable that a leading end 61a of the internal terminal 61 and a side wall 64a of the horizontal resin portion 64 are even without a step, there may be a step. The bonding wire 58, which forms wiring, is joined by ultrasonic bonding to a surface 61b of the exposed internal terminal 61. Also, the heat release plate 51 is fixed with the adhesive 56 to the lower side vertical resin portion 65.
The insert terminal case 57 is formed by a lead frame 70 disposed in a die, the lead frame 70 being inserted in the resin case 59 by injection molding, and an unnecessary terminal coupling portion 71 being cut off. The terminal coupling portion 71 is a portion that couples the internal terminals 61.
FIGS. 21A and 21B are illustrations showing a terminal coupling portion 71 cut off from the lead frame 70. FIGS. 21A and 21B are enlarged views of a B portion of FIG. 20B. FIG. 21A is an illustration before cutting. FIG. 21B is an illustration after cutting.
A downward pressurizing force Fp is applied to an upper support body 85, thereby sandwiching the lead frame 70 and horizontal resin portion 64 between the upper support body 85 and a lower support body 87. Next, the terminal coupling portion 71 protruding from the resin case 59 and the horizontal resin portion 64 of the resin case 59 fixed to the lead frame 70 is cut off from the lead frame 70 by a cutting blade 86 moved upward in a G direction. As positioning of the cutting blade 86 is carried out via the lower support body 87 with the side wall 64a of the horizontal resin portion 64 as a reference, a distance J1 between the leading end 61a (cutting place V) of the internal terminal 61 and the side wall 64a of the horizontal resin portion 64 can be shortened further when a cutting blade 86 of tie bar cutting is moved upward from below in the G direction than when the cutting blade 86 is moved downward from above. Furthermore, a movement in the G direction is preferable as the surface 61b of the flat internal terminal 61 can be suppressed by the upper support body 85. Cutting of the terminal coupling portion is called tie bar cutting.
Also, Patent Document 1 discloses such that when a bonding wire is joined by ultrasound to an internal terminal forming an insert terminal case, the internal terminal is prevented from being pulled by the bonding wire and moving when a bonder is moved, and the internal terminal is prevented from lifting up from the resin case and causing defective ultrasonic bonding.
Patent Document 1: JP-A-2000-332179.
FIG. 22 is an illustration when tie bar cutting is carried out in a state wherein the pressurizing force Fp from the upper support body 85 is insufficient. A state where the pressurizing force Fp is insufficient refers to a case wherein, although the upper support body 85 contacts the internal terminal 61, the pressurizing force Fp is small. When the pressurizing force Fp from the upper support body 85 is insufficient, the upper support body 85 is lifted upward in an E direction by the upward lifting force of the cutting blade 86, and becomes deformed. Further, it may happen that the vicinity of the leading end 61a of the internal terminal 61 separates from the horizontal resin portion 64, and a gap T of 10 μm is formed under the internal terminal 61 at the ultrasonic bonding place.
FIG. 23 is an illustration when a wire bonding onto the internal terminal is carried out in a state shown in FIG. 22.
When the gap T exists under the internal terminal, a wire load F (the force by which the wire 58 is pushed down on the internal terminal 61 via a head 90) when ultrasonic bonding is carried out is not sufficiently applied to the internal terminal 61, and ultrasonic vibration is not transmitted to the internal terminal 61 to thereby decrease the wire joining ability. As a decrease in wire joining ability decreases the product lifespan, it is necessary to ensure that no gap T is formed under the internal terminal 61.
Also, the measure for preventing movement of the internal terminal when bonding is described in JP-A-2000-332179, wherein the leading end of the internal terminal is covered with resin, and is fixed to the resin case so that the internal terminal does not move. This is a case wherein the internal terminal is fixed to the resin case after the boundary portion between the internal terminal and terminal coupling portion is cut. Therefore, there is no problem of a gap under the internal terminal formed in a step of cutting the terminal coupling portion off from the internal terminal after the internal terminal is fixed to the resin case.
An object of the invention is to provide a semiconductor device, and a method of manufacturing the semiconductor device, such that the generation of a gap under the internal terminal when cutting the terminal coupling portion from the internal terminal is restricted, thus resolving the heretofore described problem.